Mulling mill



June24, 1941. 'D N S Y 2,246,846

MULLING MILL' Filed Jan. 31, 1940 5 ShfiBW-Shet 1 v INVENTOR 124/1054, EflE/wzwy Jun; 24, 1941. D. E. HENNESSY MULLING MILL Filed Jan. 31, 19403 Sheets-Sheet 3 Patented June 24, 1941 STATES PATENT OFFICE MULLINGIVHLL Daniel E. Hennessy, Leominster, Mass. Application January 31,1940, Serial No. 316,550

4 Claims. (CI. 83-45) This invention relates to mulling mills intendedparticularly for mulling pigment for paints. It has for its object aproduct of a mill of this general character which will be very simple ofconstruction, easily taken apart for cleaning, and producing a mulledproduct of great uniformity and of any required degree of fineness. Themill operates upon the principle that if an annular muller or cup bepressed against the face of a large rotating mulling disk and heldagainst bodily travel therewith the annular muller will be set intoindependent rotation. While prior devices embodying this broad principlehave been proposed they have not been satisfactory in practice onaccount of their inability to control the grinding process. It istherefore the object of the invention to improve prior mechanisms to anextent which will permit their use in obtaining high quality grindsunder production conditions. A further object is to provide a mullingmill in which the annular and disk members will automatically form theirmating surfaces into optically fiat condition. A further object is toimprove the feeding and mixing of the material prior to the mullingaction. Additional objects will appear from the following descriptionand claims.

The invention will now be described in connection with the accompanyingdrawings, in which:

Fig. 1 is a side elevation, partly broken away, of a four-cup mullingmill constructed in accordance with my invention;

Fig. 2 is a detail of one form of platen mount- Fig. 3 is a transversesection through a portion of the mechanism shown in 1; taken on line 33of Fig. 4;

Fig. 4 is a top plan view of the mulling disk, taken on line i-A of Fig.3 and partially broken away;

Fig. 5 is a top plan of the machine shown in Fig. 1;

Fig. 6 is a fragmentary section on line 6-5 of Fig. 3;

Fig. 7 is an enlarged detail of the grinding portion of one of the cups;Fig. 8 is a section on line 8-8 of Fig. 7; and Fig. 9 is a sectionaldetail of a modification.

The machine is carried upon a plurality of uprights [0 from which issupported, as by brackets I I, a generally circular support l2. Thissupport is hollowed out as at E3 to form a drip pan for cooling water aswill be described below, and at its periphery carries a plurality ofrolls M to support a rotatable platen 15. In order to stant temperature.

secure an even bearing of all of the rolls on the platen they arepreferably made individually adjustable in the manner shown in Fig. 2.For this purpose the member I2 is provided with outwardly extendingbosses l6 into each of which a screw ll is threaded. Adjustable upon thescrew is an eccentric bearing member it upon which roll It may turn,this eccentric portion having a flange l9 held in place by the screwhead 26 and serving to adjust the eccentric and also to hold the roll inplace.

The member I2 has a vertical opening 2| in its center in whichanti-friction bearings 22 are mounted so as to support a vertical shaft23.

1 The platen I5 is keyed to this vertical shaft at at so that as theshaft is turned the platen will be rotated upon the supporting rolls Il. The top of the platen is formed with an annular ledge 25 and withinterrupted intermediate and inner ledges 26 and 2'! upon which themulling disk 28 rests. The mulling disk may in certain cases be madeintegral with the platen, but as it is usually desired to form it frombonded abrasive the separate platen is desirable. The several ledges arepreferably connected by ribs 29 at a lower level so that the wholeinterior of the platen below the stone may form a single large waterchamber 30, by circulation of water through which the disk may be keptat a con- Water is supplied to this chamber through a vertical pipe 3|threaded into a socket 32 in the upper end of the shaft 23, this socketcommunicating with the spaces 33 between the ledges 21 through radialholes 34. The water passes radially outwardly and runs oif throughdownwardly extending tubes 35 arranged in the ribs 29 adjacent the ledge25. The tubes 35 extend into the drip pan l3, which collects the waterand delivers it through a suitable drain 36.

The large mulling disk 28 rotates with the platen, being held to theshaft 23 by a large key 31. Resting upon it, but held against bodilyrotation with it, are a series of annular mullers w shown in detail inFigs. 7 and 8, and generally formed of bonded abrasive. These latter areheld in shouldered portions 4| of cup members 42 which may convenientlybe formed of cast iron. As will be seen from Fig. 3, the shoulders ofthe cup members are so formed as to permit the mullers alone to contactthe large disk 28. These cup members, however, serve both to exert thenecessary pressure between the mullers and the disk and as receptaclesinto which the pigment and vehicle to be mulled are placed.

The cup members have inwardly extending lateral ribs 43 supporting a hubmember 44 spaced out of contact with the disk 28, the ribs preferablybeing angled to exert a downward propelling action upon the materialwithin the cup. An anti-friction bearing 45 of the lateral thrust typeis seated in the upper part of each hub and receives centrally a plug45. The plug has a conical depression in its upper surface whichreceives the pointed end 41 of a rod 48 slidable vertically in a hubportion at formed in a spider 58 supported from the uprights It.

To regulate the pressure of the annular grinding stones against thelarge disk the rods 48 are forced downwardly with a regulable pressure.For this purpose a lever is pivoted to the spider at 52 adjacent each ofthe rods and carries a screw 53 in contact with the upper end of therod. A weight 54 slides on each of the levers and is engageable in anyone of a series of notches 55 therein. It will be seen that by shiftingthe weight the downward force exerted on the annular mullers can beregulated accurately and held constant irrespective of the nature of thematerial being mulled, and that by reason of the fact that this downwardforce is transmitted to the cups through the pointed lower ends 57 ofthe rods only it'will be distributed throughout the periphery of themullers with perfect uniformity.

The machine is operated by gearing 6i] driven from a pulley 6! or anyother suitable source. This causes the large disk to revolve and due tothe fact that the outer part of the large disk moves faster than itsinner portion the mulling cups will be caused to revolve in thedirection of the arrow G2 in Fig. 5. If material to be ground is placedinside of the cups it will gradually be carried underneath the annularmullers and distributed upon the surface of the large disk. As thelatter rotates, the mulled material may be pushed off it by doctorblades 63 onto a ledge 54 of the platen, from where it may be gatheredby a doctor blade 65 and delivered into any suitable receptable.

One advantage of the described construction is that the annular mullersare held against the flat disk in such a way that they can be rotated byit on their own axes at the natural speed determined by their size andposition, and that the pressure on the mullers is kept centralized andwithout restraint upon their tendency to lie flat on the disk. Thisresults in the mullers and disk grinding themselves so as to presentoptically flat mating surfaces, whereas other types of mulling orgrinding machines require frequent dressing. It may be advantageous incertain cases to constrain the several annular mullers to rotate atidentical rates, preferably without varying their freedom as a whole torotate at their natural speed. This prevents local conditions fromcausing an abnormal speed of rotation of one of the mullers, and insuresuniformity in the product delivered by the several mullers. providedwith a ring gear 70 meshing with a For this purpose each muller isfloating ring gear ll held on a hub 12 of the spider 50 by a detachableflange 13. Since the ring gear H is free to rotate the only constraintit imposes on the mullers is that they all rotate at the same speed,whatever that may be with respect to the disk.

I claim:

1. A mulling mill comprising a mulling disk, means for revolving thedisk upon a vertical axis, a plurality of paste retaining cups, eachbearing an annular muller upon its lower surface in face contact withthe disk, an arm pivota'lly carried above each of the cups, a weightadjustably mounted on each arm, a rod extending from each arm into oneof the cups, and a universal bearing between each rod and its respectivecup.

2. A mulling mill comprising a mulling disk, means for revolving thedisk upon a vertical axis, a mix retaining cup having an annular mullingsurface in face contact with the disk, an arm pivoted above the cup, aweight adjustably mounted on the arm, a rod extending from the arm intothe cup, a universal bearing within the cup and engaging the rod, and anopenwork support carried by the cup and carrying the bearing andcomprising slanting vanes, said support acting to agitate and forcedownwardly material within the cup as the latter is rotated upon itsindividual axis by frictional contact with the disk.

3. A mulling mill comprising a frame, a platen, anti-friction supportson the frame for the platen, means for rotating the platen, a mullingdisk on the platen, a plurality of mix retaining cups, each having anannular mulling surface in face contact with the disk, a non-rotatingspider carried by the frame above the platen, an arm pivotably carriedby the spider above each of the cups, a weight adjustably mounted oneach arm, a rod slidable in the spider under each arm and extending intothe respective cup, an openwork support within each cup comprisingspaced slanting vanes assisting the downward passage of mix as the cuprotates, a combined radial thrust anti-friction bearing carried by saidsupport, and a combined radial-thrust connection between the rod and thebearing.

i. A mulling mill comprising a frame, a platen, anti-friction supportson the frame for the platen, means for rotating the platen, a mullingdisk on the platen, a plurality of mix retaining cups, each having anannular mulling surface in face contact with the disk, a non-rotatingspider carried by the frame above the platen, an arm pivotably carriedby the spider above each of the cups, a weight adjustably mounted oneach arm, a rod slidable in the spider under each arm and extending intothe respective cup, an open-work support within each cup permitting thedownward passage of mix, a combined radial thrust anti-friction bearingcarried by said support, and a combined radial-thrust connection betweenthe rod and the bearing. 7

DANIEL E. HENNESSY.

